Firstly the top bolt for the shock? No it screws into threads in the frame. I'll double check the parts book but I'm 99% certain it doesn't use a nut.
As for the oil around the slave? It's perfectly normal as the slave acts on a thrust assembly at the rear of the gearbox which is lubricated by oil from the gearbox. It is sealed by that o-ring you can see on the slave and oil is prevented from travelling up the pushrod that operates the clutch by cone seals that go over the rod. The clutch is immediately behind the engine like a car, not at the back of the box.